Enlarge Image Turn on. A computer simulation of the expected result from a biological AND gate (top) and the actual data (bottom). Credit: J.Bonnet et al., Science (28 March, 2013) For the first time, synthetic biologists have created a genetic device that mimics one of the widgets on which all of modern electronics is based, the three-terminal transistor. Like standard electronic transistors, the new biological transistor is expected to work in many different biological circuit designs. Together with other advances in crafting genetic circuitry, that should make it easier for scientists to program cells to do everything from monitor...